The present disclosure relates to a system on chip (SoC). More particularly, the present disclosure relates to aspects of a system on chip including a secure joint test action group (JTAG) system and a secure debugging method.
A system on chip (SoC) in a mobile product has become increasingly complex. For example, a mobile phone may include an application processor (AP), a modem, a global navigation satellite system (GNSS), a wireless-fidelity (Wi-Fi) device, a Bluetooth device, and multiple other integrated systems. Debuggging to verify functions of the integrated system on chip and mobile product has become important.
The system on chip performs a secure debugging operation. Only an authenticated user may perform the debugging so as to protect important security data of the system and the user. The secure debugging operation of the system on chip may be performed through a secure joint test action group system. The system on chip including the secure joint test action group system may store debug authentication information or a debug authentication result of the secure debugging operation. However, if the system on chip is in a low power mode, power supplied to the system on chip is stopped, such that important debug authentication information or an important debug authentication result can be lost. Therefore, the system on chip may not perform a continuous secure debugging operation in the low power mode.